Inspired by reading one of John Muir's books about the wilderness, President Theodore Roosevelt wrote Muir and asked him to take him camping in the Yosemite wilderness. Traveling west by train, Roosevelt arrived in Raymond, California on May 15, 1903. Finally leaving an adoring crowd, "Teedie" and "Johnnie" rode off on horseback alone. They spent four days camping, forging a friendship through their mutual love of nature. Johnnie was the teacher, showing the president the giant sequoias and explaining how Yosemite Valley was formed. He taught Teedie how vulnerable the wilderness areas were and inspired him to return to Washington determined to help protect them. In thin-line, loose, sketchy drawings, washed with watercolors, the illustrator Mordicai Gerstein perfectly captures the personalities of the lanky, laconic Muir and the stocky, ebullient Roosevelt. He captures the humor and happiness of one camping trip that has benefited us all.